Tripod jack



Aug. 1'7, 1943. R. 1.. DIERCKSMEIER EIAL 2,327,130

TRIPOD max Filed July 25, 1941 3 Sheets-Sheet l BY v mfg/2225f.

Aug. 17, 1943- R. L. DIERCKSMEIER ET L 2,327,130

TRIPOD JACK Filed July 25, 1941 'SSheets-Sheet 2 Aug. 17, 1943. R. 1.. DIERCKSMEIER ETAL 2,327,180

' TRIPOD JACK Filed July 23, 1941 5 Sheets-Sheet 5 Q g 1NVENTOR.

ATToRNEx a Patented Aug. 17, 1943 Roy L. Diercksmeier, Chicago,

111., and Edward M.

Pfauser, Elm Grove, Wis., assignors to Blackhawk Mtg. (10., of Wisconsin Milwaukee, Wis a corporation Application July 23, 1941, Serial No. 403,000 '1 Claims. (01. 254-1) Our invention relates generallyto improvements in the art of elevating, propping and lowcrime diverse objects such as airplanes; and relates more specifically to various improvements in the construction and operation of tripod jacks of the portable type and which are adjustable to meet various conditions of use.

A general object of our invention is to provide a new and useful tripod prop and jack assemlolage which is simple and durable in constructlon, and which is moreover highly emcient in use.

It has heretofore been proposed as shown in United States Patent No, 2,227,460, granted January 7, liidl, to Otto Morgensen, Jr., to provide a portable airplane jacls having a tripod, an upright object=engagingmember slidable centrally of the tripod, and mechanical advantage means such as a hydraulic jack or ram for moving the worls engaging member; and while this prior patented airplane jack is quite satisfactory and efiective for most of its intended uses, it is relatively cumbersome and complicated, and is not adapted to meet all conditions of use which arise when lifting, propping and lowering planes. A lack and prop structure of this kind must be compact but powerful, quickly manipulable and reliable in action, and readily transportable and conveniently applicable to the plane elements in crowded and restricted quarters. Such an assemblage should also be sufliciently stable to resist tilting or other displacement when in use,

and the lifting power should preferably be applied to the work as directly as possible; and pro-, vision should also be made for efiecting rapid and universal adjustment of the object engaging plunger relative to the work and for placing and locking the plunger prop in any position of vertical adjustment. While the previously patented iacls assemblage does meet many of the specific requirements, it fails to meet all of them in a satisfactory manner, and although the prior structure makes provision for elevating bodies distances greater than the length of the stroke of the hydraulic jack and for locking the work engaging prop in some positions of vertical adjustment, this locking can only be effected at fixed intervals and is not universal throughout the entire range of adjustment.

It is therefore a more specific object of our present invention to provide an improved jack and prep for airplanes or the like, Which most efiectively meets all of the above mentioned conditions and requirements, and which is extremely flexible in its adaptations and uses.

Another specific object of the present invention is to provide a sturdy and extremely simple tripod Jack assemblage having enormous powerconsidering the total space occupied, and which can be readily bodily transferred from place to place and utilized in cramped localities.

A further specific object of this invention is to provide an improved prop having mechanical advantage'means for varying the effective length thereof, and in which the work engaging member may be quickly and efiectively placed and locked in any desired position of adjustment.

Still another specific object of the invention is to provide a simple and strong framework for a tripod or the like, the fixed height and spread of which can be conveniently altered, and which can be readily assembled or dismantled for compact storage.

An additional specific object of our invention is to provide an improved hydraulic jack assembly which is especially adapted for use as a mechanical advantage means in conjunction with an airplane tripod or prop.

Another specific object of this invention is to provide various improvements in the details of construction of hydraulically actuated tripod jack assemblages of the Portable type, whereby the cost of construction oi. such devices is reduced to a minimum, while the efi'lciency thereof is enhanced to a maximum.

These and other specific objects and advantages of the invention will be apparent from the following detailed description.

A clear conception of the several features constituting the present improvement, and of the manner of constructing and of manipulating portable hydraulic tripod jacks embodying the invention, may be had by referring to the drawings accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the various views.

Fig. 1 is a front elevation of one of the improved hydraulic tripod jack assemblages of minimum height, showing the work-engaging plunger in lowermost position, and also having a portion of the supporting legs on one side broken away;

Fig. 2 is a similar elevation of one of the improved assemblages drawn to reduced scale and having a tripod of somewhat greater initial height;

Fig. 3 is another similar elevation of one of the improved assemblages likewise drawn to reduced scale and having a tripod structure of still greater initial height;

Fig. 4 is a greatly enlarged central vertical section through the improved hydraulic jack or ram, with the plunger in lowermost position and the work-engaging member lowered, the medial portion of the ram having been broken away;

Fig. 5 is a side elevation of one of the upper leg attachments and of one of the jack carrying handles;

Fig. 6 is a side elevation of fragments of the ram plunger and upper adjusting ring. showing the locking pin coacting with these elements;

Fig. 7 is a sectional view similar to the upper portion of Fig. 4, but showing the ram plunger elevated and locked against retraction relative to the ram cylinder and tripod;

Fig. 8 is a. bottom view of the ram cylinder showing the mode of attachment-of the three centering braces; and

.Fig. 9 is a section through one of the tripod supporting feet. v

While our invention has been shown and described herein by way of illustration, as being embodied in three legged hydraulic tripod jack assemblages of the portable type especially adapted for airplane services, it is not our desire or intent to thereby unnecessarily restrict the scope or utility of the improvement, and the term tripod is intended to apply to prop assemblages having any number of supporting legs.

Referring to the drawings, the improved airplane jack shown therein comprises in general, a tripod consisting of an upper hub provided with a central vertical partially threaded bore I l and having setsof integral radiating ears l2 to which supporting legs l3, I3, l3 are removably and pivotally attached by means of transverse bolts or pins l4; a mechanical advantage device or hydraulic ram consisting of an elongated upright cylinder I5 removably confined at its upper end within the hub bore I l by set screws l6 coacting with a groove, and having its lower end sealed by a cup shaped element or head I1, and a plunger I8 coacting with and reciprocable within the bore of the cylinder l5 and being provided with an elongated plunger rod i9 slidable in an upper guiding and packing gland a vertically adjustable work-engaging member or saddle 2| carried at the top of a spindle 22 having screw thread coaction with a bushing 23 which is detachably secured within the upper recessed end of the rod l9; and centering braces 24, 24', 24 of selected lengths connected to cars on the ram cylinder head IT by removable bolts 25, and with feet 25 secured to the lower ends of the legs I 3, by means of other removable bolts 21.

The central upper hub IU of the tripod prop is preferably formed in one-piece of durable metal, and the leg suspension pins 14 are removable from the integral ears I2 so as to permit quick detachment of the legs l3 from the hub Ill.

One side of the hub Ill may also be provided with a handle 28 for facilitating adjustment and transportation of the jack structure, and a locking pin 29 may also be suspended from the hub I 0 by means of a chain 30 or the like. The tripod supporting legs l3, l3, [3" may be formed of stock tubing and of any selected length in order to provide a tripod of predetermined height, as shown in Figs. 1, 2 and 3 respectively; and the upper ends of these tubular legs l3 may be provided with fittings 3| adapted to coact with the pins l4 as shown in Fig. 4, while the lower leg ends may be snugly fitted within the feet 26 and detachably secured thereto by dowel pins 32 as illustrated in Fig. 9. The radial tripod braces 24, 24', 24" may also be formed of selected length corresponding to the lengths selected for the legs I3, l3, l3" respectively, as shown in Figs. 1, 2 and 3 and these braces 24 are preferably rigidly but removably attached to the cylinder head ll and feet 26 with the aid of the pins or bolts 25, 21 respectively, so as to permit the legs 13 to be folded inwardly toward the cylinder l 5 when it is desired to collapse the tripod. The hub I0, legs l3, braces 24, and feet 26 just described, constitute the tripod assembly, and as previously indicated, any desired number of legs 13 may be provided.

The improved mechanical advantage device or hydraulic ram, comprising the elongated cylinder 15, lower head I], plunger I8, and elongated plunger rod I9, is normally fixedly mounted so that the plunger l8 and its rod l9 may be elevated by the admission of liquid under pressure tothe lower displacement chamber 33 of the cylinder through a port 34, and may be lowered by gravity when the liquid pressure is relieved through this same port 34. The required liquid pressure may be derived from any desired source such as a pump mounted on one of the legs 13 and connected to the port 34 by a flexible tube or hose; and the ram piston or plunger l8 which snugly slidably engages the bore of the cylinder I5, is also provided with a cuppacking 35 near its lower end, and with an abutment 35 at its opposite end adapted to engage a similar abutment 31 at the lower end of one of the elements of the gland 20, in order to positively limit the upward stroke of the plunger It. The elongated plunger rod I9 which is snugly but slidably confined within the upper gland 20, has its lower end either detachably secured to the plunger I8 as shown, or formed integral therewith; and the medial portion of this rod [9 is provided with a series of equally spaced parallel through holes 38 with any of which the pin 29 may be caused to cooperate to lock the plunger and rod against retraction or lowering.

In order to permit such universal locking of the plunger and rod I!) to be effected when the plunger I8 is in any position of vertical adjustment relative to the tripod, we have provided special mechanism such as shown in detail in Figs. 4, 6 and 7, at the upper extremity of th ram. Besides the vertically adjustable spindle 22 which carried the work-engaging saddle 2| and has screw thread coaction with the sleeve 23 mounted in the upper end of the rod l9, and the pin 29 coacting with the holes 38, this improved adjusting mechanism comprises a collar 39 internally screw threaded for coaction with external threads 40 at the upper extremity of the ram cylinder l5 and having a lower outer flange 4| and an upper inner flange 42; an annular stop element 43 surrounding the lower portion of the collar 39 and rigidly attached to the top of the hub Ill by cap screws 44, the element 43 having an upper inwardly directed flange 45 adapted to engage the lower collar flange 4| so as to limit the upward adjusting movement of the collar 39; and a seating ring 46 resting upon the upper collar flange 42 and detachably secured to the collar 39 by means of spring pressed pins 41, and having a series of radial recesses 48 in the upper surface thereof adapted to coact with the locking pin 29 as shown in Figs. 6 and 7.

With this improved adjusting assemblage, the externally screw threaded spindle 22 coacting with the sleeve 23 carried by the plunger rod l9,

may first be adjusted when the tripod jack has been properly positioned ben ath the object which is to be raised, so as to cause the saddle member Hi to initially engage the work. The ram plunger l8 and rod [9 may thereafter be elevated by the admission of liquid under pressure to the chamber 33 so as to lift the object any desired amount within the stroke of the ram plunger it. If this desired lift places one of the holes 36 in alinement with a diametrically opposite set or" the recesses lit in the ring at, the locking pin 29 may be inserted in the alined hole and recesses as shown in Fig. 7, to thereby positively retain the member at and the work in the desired elevated position even if the pressure in the ram displacement chamber 33 should drop. In case none of the holes 38 are disposed in alinement with a set of the recesses 48 when the desired lifting has been efiected, the collar 39 may be rotated to move the seating ring d6 upwardly to an extent silfificient to cause a set of diametrically opposite recesses 68 to properly coact with the hole 38 nearest to and above the ring to, whereupon the locking pin 29 may be inserted in order to positively prevent lowering of the Work. or elevated object. In this manner any desired position of vertical adjustment of the assemblage may be quickly and readily maintained without lowering the work to any extent; and in order to facilitate the adjusting operation, the exterior of the saddle member 2i and ring 46 may be knurled and the exterior of the upper portion of the rollar 3d may be roughened for application of a wrench, as shown. It is also important that the lowermost hole 38 in the rod l9, be located the proper dis- .tance above the plunger [8, so that this lowest hole will be above the ring 46 when the abutments 35,:38 coact with each other, and the range of vertical adjustment of the collar 39 should also be at least equalt'o' or slightly greater than the distance between successive holes 33.

From the foregoing detailed description, it will be apparent that our present invention provides an improved tripod jack which is extremely simple, compact and sturdy in construction, and which can be readily adjusted to elevate extremely heavy objects and locked in adjusted position. The fixed height of the improved tripod can be conveniently varied to meet difierent conditions of use, and the jack unit can be easily transported with the aid of the handle 28 on the hub l8 and with the aid of an additional handle 69 associated with the ram cylinder, and the assemblage can also be readily collapsed for convenient storage by merely removing either the bolts 25 or the bolts 2i. The improved ram assemblage besides providing enormous power, is extremely stable and readily manipulable, and the adjusting mechanism associated with the upper hub portion of the ram permits universal positioning of the workengaging member and locking thereof in any desired position. The tripod assemblage can be manufactured at moderate cost by virtue of the fact that the legs are formed of relatively standard stiif tubing, and this tripod assemblage besides being formed to withstand extreme stresses, can also be positioned in relatively cramped quarters without sacrificing stability.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of use, herein shown and described, for various modifications within the scope of the claims may occur to persons skilled in the art.

We claim:

1. In combination, a tripod, a hydraulic ram cylinder fixedly secured to said tripod, a plunger movable in said cylinder and having a series of holes therethrough, a work-engaging member carried by said plunger, means for eifecting adjustment of said member along the axis of and relative to said plunger, 9. reaction element adjustable along said cylinder, and a pin cooperable with said element and with said holes to retain said plunger in any position of vertical adjustment within the limits or movement thereof.

recesses of said ring and with said holes to retain said plunger in any position of vertical adjustment.

3. In combination, a tripod, a fluid pressure actuated ram having a cylinder fixedly secured to said tripod and having a plunger movable in said cylinder, said plunger being provided with a series of spaced holes extending therethrough, a workengaging member carried by and adjustable axially along said plunger, a collar adjustable along said cylinder, a radially recessed ring carried by said collar, and a pin cooperable with the recesses of said ring and with said holes to retain said plunger in any position of vertical adjustment.

4. In combination, a tripod having a central axis, a ram having a cylinder fixedly secured to said tripod concentrically of said axis, a plunger movable along said cylinder and having a series of depressions, a work engaging member carried by said plunger, means for efiecting ad ustment of said member along said axis and relative to said plunger, an annular reaction element adjustable along said axis and relative to said cylinder, and a pin cooperable with said annular element and with said plunger depressions to retain said memher in any position of vertical adjustment within the limits of movement of said plunger.

5. In combination, a tripod having a central axis, a ram having a cylinder fixedly secured to said tripod concentrically of said axis, a plunger movable along said cylinder and having a series of depressions, a work engaging member carried by said plunger, means for efiecting adjustment of said member along said axis and relative to said plunger, an annular reaction element adjustable along said axis and relative to said cylinder, a recessed ring carriedby said element, and a pin cooperable with the-recesses of said ring and with said plunger depressions to retain said member in any position of vertical adjustment.

6. In combination, a tripod having a central axis, a ram having a cylinder fixedly secured to said tripod concentrically of said axis, a plunger movable along said cylinder and having a series of depressions, a wor engaging member carried by said plunger, means for efiecting adjustment of said member along said axis and relative to said plunger, a, reaction collar adjustable along said axis and relative to said cylinder, a radially recessed ring resting upon said collar, and a pin cooperable with theradial recesses of said ring and with said plunger depressions to hold said work engaging member and said plunger in any position or vertical adjustment.

'I. In combination, a tripod having a centralaxis, a ram having a cylinder fixedly secured to said tripod concentrically of said axis, a plunger movable along said cylinder and having a, series of depressions, a work engaging member carried by said plunger, means for eflecting adjustment of said member along said axis and relative to said plunger, a reaction collar screw threaded upon said cylinder for adjustment along said axis, a recessed ring rotatably supported upon said collar, and a pin cooper-able with said ring recesses and with said plunger depressions to lock the 5 latter in various vertical positions.

ROY L. DIERCKSLJEIER. EDWARD M. PFAUSER. 

